Danshen, also known by its botanical name Radix Salvia Miltiorrhizae, is one of the most common-used traditional Chinese medicines (TCM) in China. It mainly consists of two categories of chemical ingredients, namely the water-soluble and the non water-soluble. Dating back to the early 20th century, the chief research on these ingredients has always been concentrated on the non water-soluble ones represented by tashinone, and achieved great success after decades of efforts. It is not until the beginning of 1980s that, after a lot of work, our scientists have studied Danshen's water-soluble ingredients, and first reported structure of the water-soluble one, Danshensu. Afterward, tens of water-soluble ones have also been discovered one after another with the definitive chemical structure. Subsequently it has been proven that, of the active ingredients in Danshen's water-soluble ones, the most effective is phenolic acid compounds, such as salvianoic acid A(1), B(2), C(3), D(4), E(5), F(8), G(9), H(11), I(12), J(13), rosmarinci acid (6), alkannic acid (7), isosalvianoic acid C(10), glucoside of rosmarinci acid(14), etc. (Lian-Niang Li, J. Chinese Pharmaceutical Sciences 1997, 6, 57-64). Pharmacologically, a variety of activities of these salvianolic acid compounds have already been reported. For example, Salvianolic acid A has significant protecting effects on cardiac muscle cell caused by ischemic reperfusion (I/R), and totalphenolic acid has strong anti-arrhythmia effect induced by I/R; Salvianolic acid A, B and totalphenolic acid have showed markedly protective effects against brain damage caused by I/R in rats by lowering content of MDA in brain tissues; there are plenty more other effects for the salvianolic acid as follows: anti-thrombus effects, protective effect on liver and kidney, anti-oxidation and inhibiting lipid super oxidation, as well scavenging puperoxide anion and free radical etc. (Du Guanhua etal, Basic medical science and clinics, 2000, 20 (5):10−14).
At present, a great number of processes of extracting Salviamolic acid have been reported, but most of them are mainly focused on passing resin column following extracting by water. For example, Takashi Tanaka et al revealed the method of extracting salvainolate (Chemical Pharmaceutical Bulletin, 1989, 37(2), 340−344). Besides, there have also been many other scientists who have adopted similar methods for extracting phenolic compounds from Danshen, such as Koji Hase et al (Planta Medica, 1997, 63, 22−26), Xu Yaming et al (China patent CN1247855A, published in March, 2000), Liu Ping et al (China patent CN1270809A, published in October, 2000), and Li Lianniang (China Patent Application No. 0114228.2, filed on September 2001). But all of above-mentioned processes for extracting have a common problem in industrialization, namely a great deal of water need to be concentrated. Because of the instability, the concentrating temperature of total salvainolic acid water decoction must be varying between 50° C. and 60° C., which accordingly will result in both the difficulties in techniques and rise in cost. Meanwhile, the lasting heating process, although between 50° C. and 60° C., will also produce a series of serious problems including instability, and therefore affect its quality and curative effect. Finally, all these problems make it almost impossible for the industrialization. Another shortcoming of these already-existing processes is that the low yield, generally between 2% and 3%, limits its application in the industry.